A weather control mechanism regulated the atmospheric conditions of Galactic City on Coruscant, a planet that functioned as the capital for both the Galactic Republic and, subsequently, the Galactic Empire. Consequently, Coruscant enjoyed a fabricated, moderate climate.
The somewhat distant orbit of Coruscant from its relatively small sun presented a climate that was not particularly hospitable for many species. However, the technological advancements and the considerable heat generated by the multi-layered urban environment mitigated this issue. Nevertheless, the troposphere-penetrating structures blanketing the galactic capital's surface significantly impacted its weather patterns, leading to the formation of peculiar and unpredictable microclimates. This was due to substantial and contrasting variations in temperature and atmospheric pressure between the higher and lower elevations within the tallest buildings.
The air in the higher echelons of the city underwent filtration processes, providing a refined atmosphere for the affluent inhabitants of the Core World. Conversely, the Coruscant undercity, obscured by the continuous vertical expansion of skyscrapers and the subsequent addition of megastructural tiers to the vast planetary metropolis, lacked such amenities. Its residents were forced to inhale the scarcely breathable, noxious emissions resulting from millennia of vehicular and factory waste across the cityscape. The average Coruscanti, dwelling in a lower-level sector, relied on manufactured air within their residences. Imperial officer Wilhuff Tarkin recalled that Coruscant's weather control was among the many luxuries present in Galactic City that were absent from his homeworld of Eriadu.
Despite the presence of weather control systems, the wealthiest citizens within Galactic City enjoyed breathing superior, purified gas tailored to their preferences. Routine scans were conducted on their buildings to detect any irregularities in gas purity, which were addressed by specialized quality-control droid teams. Furthermore, numerous visitors arriving from other worlds opted to bring their own private air supplies for the duration of their stay.
During the Imperial Era, the weather control system served to cleanse the skyscrapers of the Federal District, restoring their pristine appearance before dispersing any lingering cloud cover. When observed from space, the planet's hazy cloud layer only slightly diminished the artificial illumination emanating from Coruscant. Rainfall also occurred in other districts of Galactic City. A lightning storm manifested over the Republic Center for Military Operations during Ahsoka Tano's escape from the Republic military base during the Clone Wars. Additionally, a sizable grey cloud loomed over the Temple Precinct while the Jedi High Council deliberated on assassinating Count Dooku, the Head of State of the Confederacy of Independent Systems, as a means to resolve the galactic conflict. The Jedi Grand Master Yoda drew a parallel between the cloud obscuring Coruscant's sun and the encompassing nature of life itself to justify the Council's decision. Shortly following the end of the war and the founding of the Galactic Empire, rain descended upon Darth Vader as he entered the Grand Republic Medical Facility.
The concept of Coruscant's weather control was initially introduced in the 2014 novel titled Tarkin, penned by James Luceno. Within the Star Wars Legends continuity, the term Coruscant Weather Control pertained to the Coruscant WeatherNet, an organization responsible for managing weather conditions on Coruscant.